Magnetic field communication arrangement and method

ABSTRACT

An automotive communication method includes installing a sensor within a vehicle such that the sensor is submerged in a liquid during operation of the vehicle and/or substantially surrounded by a metallic structure during operation of the vehicle. A long wave magnetic signal is transmitted from the sensor. The signal is indicative of a condition sensed by the sensor. The signal is wirelessly received at a controller disposed within the vehicle. Receipt of the signal at the controller is responded to by adjusting a display and/or a setting within the vehicle.

BACKGROUND

1. Field of the Invention

The present invention relates to automotive communication systems, and,more particularly, to wireless automotive communication systems.

2. Description of the Related Art

Traditionally wired communication is used in vehicular communicationapplications, while radio frequency (RF) based wireless communication isemployed in some limited applications. Typically, automotive body domainapplications such as seat control, window lift, mirror adjustment, andlight control are distributed over the entire car and are interconnectedvia field bus communication systems. Current architectures have grownfast over the last decades as more and more convenience functions areintroduced to the automotive industry. In order to connect theperipherals, a large number of cables may be necessary, which increasesthe complexity of the cable harness, increases the weight of the car,and increases the costs of the car. The increase in the number of cablesmay also lead to reliability problems in areas where the cable harnessis mounted on moveable parts such as the side mirror, doors, seat, etc.

In order to avoid the above-described problems associated withhard-wired communication systems, it is known for radio frequency (RF)wireless communication to be employed between and within various systemswithin a vehicle, such as an automobile. Attaining reliable RFcommunication with good performance is problematic within a vehicle,however, because RF communication is deeply affected by fading due tomultipath, and human and metallic obstructions inside the vehicle.

Recently, long wave (LW) magnetic signals based communication has beenadopted at IEEE 1902.1 standard, also known as RuBee. Magnetic wavecommunication has an added advantage of passing through metals andliquids and thus can be used at locations which arehazardous/hard-to-wire or require precise localization (e.g.,computation of the two-dimensional or three-dimensional position of eachnode relative to each other).

What is neither disclosed nor suggested in the art is a communicationsystem for a vehicle that avoids the above-mentioned problems anddisadvantages associated with known wired communication systems and withRF communication systems.

SUMMARY OF THE INVENTION

The present invention is targeted towards using magnetic signals forcommunication in vehicular applications. The present invention may beapplicable for automotive networks as well as for other applications.For example, the principles of the present invention may be applied toindustrial networks, cargo, airplanes, ships, etc. However, a majoradvantage of magnetic communication over RF based wireless communicationis better performance in the presence of metallic/non-metallicobstructions. Thus, because vehicles typically have a large number ofobstructions and structures confined to a small space, the utilizationof magnetic communication according to the present invention may enablesensors and other wireless devices to be placed at locations with thevehicle at which it has been heretofore impossible to place suchsensors.

The invention comprises, in one form thereof, an automotivecommunication method including installing a sensor within a vehicle suchthat the sensor is submerged in a liquid during operation of the vehicleand/or substantially surrounded by a metallic structure during operationof the vehicle. A long wave magnetic signal is transmitted from thesensor. The signal is indicative of a condition sensed by the sensor.The signal is wirelessly received at a controller disposed within thevehicle. Receipt of the signal at the controller is responded to byadjusting a display and/or a setting within the vehicle.

The invention comprises, in another form thereof, a tractor-trailerarrangement including a trailer having at least one wall separating aninterior of the trailer from an ambient environment. A door having anopen position and a closed position is disposed in one wall. A wirelessdoor contact sensor senses whether the door is in the open position orthe closed position, and transmits a sequence of long wave magneticsignals. Each of the signals is indicative of whether the door is in theopen position or the closed position at a respective point in time. Atractor unit is mechanically coupled to the trailer. The tractor unitincludes a controller receiving the long wave magnetic signals from thesensor, and controlling presentation of information on the audio speakerand/or video display dependent upon the received signals.

The invention comprises, in yet another form thereof, a method ofmonitoring the presence of vehicles within a predetermined space,including broadcasting a respective long wave magnetic identificationsignal from each of a plurality of vehicles. Each of the identificationsignals uniquely identifies the vehicle from which the signal isbroadcasted. A plurality of long wave magnetic signal readers are usedto receive the identification signals from the vehicles. Each of thereaders receives the identification signals from vehicles disposedwithin a respective portion of the predetermined space. The receivedidentification signals are automatically responded to by recording theidentifications of the vehicles in association with each of the portionsof the predetermined space and/or transmitting a response signal.

The invention comprises, in still another form thereof, a method oflocking and unlocking a door of a vehicle. A long wave magnetic signalis transmitted from a keyfob. The signal includes an identifiercorresponding to a respective vehicle. The keyfob includes an actuatablecontrol, such as a pushbutton, for example. The long wave magneticsignal is transmitted in response to the actuatable control beingactuated by a user. The long wave magnetic signal is received at therespective vehicle. The identifier is recognized as corresponding to therespective vehicle. The recognizing is performed within the respectivevehicle. In response to the recognizing, a door of the respectivevehicle is automatically changing from a locked state to an unlockedstate or from an unlocked state to a locked state.

An advantage of the present invention is that magnetic wirelesscommunication may operate reliably in the presence of metal, liquids,dirt, etc., and thus can be employed in harsh environments.

Another advantage is that magnetic wireless communication has very lowsignal strength outside of the intended range, and hence providesgreater security and reduced interference with other networks outside ofthe intended range.

Yet another advantage is that magnetic wireless communication has almostnegligible electromagnetic interference (EMI), and hence betterelectromagnetic compatibility (EMC).

Still another advantage is that magnetic wireless communication-baseddevices can be embedded into metallic components and parts.

A further advantage is that magnetic wireless communication-baseddevices transmit at very low power, and thus are not hazardous to thehuman body and may have long battery lives.

A still further advantage is that magnetic wireless communicationprovides greater flexibility and accessibility than does wirednetworking. For example, magnetic wireless communication-based devicesmay be employed in hard-to-wire areas.

Another advantage as compared to hard-wired systems is the relative easeof aftermarket/ad hoc installations.

BRIEF DESCRIPTION OF THE DRAWINGS

The above mentioned and other features and objects of this invention,and the manner of attaining them, will become more apparent and theinvention itself will be better understood by reference to the followingdescription of an embodiment of the invention taken in conjunction withthe accompanying drawings, wherein:

FIG. 1 a is a schematic side view of one embodiment of a magnetic fieldcommunication arrangement of the present invention.

FIG. 1 b is a schematic top view of the magnetic field communicationarrangement of FIG. 1 a.

FIG. 2 a is an overhead view of nodes placed for localizing at the frontand rear of a vehicle according to one embodiment of the presentinvention.

FIG. 2 b is an overhead view of nodes placed for localizing at the fourcorners of a vehicle according to one embodiment of the presentinvention.

FIG. 2 c is an overhead view of nodes placed for localizing at alllocations of a vehicle according to one embodiment of the presentinvention.

FIG. 3 a is a schematic diagram of a respective magnetic card readerbeing assigned to each parking spot within a parking lot according toone embodiment of the present invention.

FIG. 3 b is a schematic diagram of a respective magnetic card readerbeing assigned to each pair of side-by-side parking spots within aparking lot according to another embodiment of the present invention.

FIG. 3 c is a schematic diagram of a respective magnetic card readerbeing assigned to each pair of end-to-end parking spots within a parkinglot according to yet another embodiment of the present invention.

FIG. 3 d is a schematic diagram of a respective magnetic card readerbeing assigned to each group of four parking spots within a parking lotaccording to still another embodiment of the present invention.

FIG. 4 a is a side sectional view of a magnetic field-basedcommunication device disposed within the structure of a vehicle engine.

FIG. 4 b is a side sectional view of a magnetic field-basedcommunication device disposed within the structure of a vehicle coolantradiator.

FIG. 4 c is a side sectional view of a magnetic field-basedcommunication device and motor assembly disposed within the structure ofa vehicle windshield washer reservoir.

FIG. 5 is a flow chart illustrating one embodiment of a magnetic fieldcommunication method of the present invention.

FIG. 6 is a flow chart illustrating one embodiment of a method of thepresent invention for monitoring the presence of vehicles within apredetermined space.

FIG. 7 is a block diagram of one embodiment of a parking garagearrangement of the present invention.

Corresponding reference characters indicate corresponding partsthroughout the several views. Although the drawings representembodiments of the present invention, the drawings are not necessarilyto scale and certain features may be exaggerated in order to betterillustrate and explain the present invention. Although theexemplification set out herein illustrates embodiments of the invention,in several forms, the embodiments disclosed below are not intended to beexhaustive or to be construed as limiting the scope of the invention tothe precise forms disclosed.

DETAILED DESCRIPTION

The embodiments hereinafter disclosed are not intended to be exhaustiveor limit the invention to the precise forms disclosed in the followingdescription. Rather the embodiments are chosen and described so thatothers skilled in the art may utilize its teachings.

Referring now to the drawings, and particularly to FIGS. 1 a-b, there isshown one embodiment of a magnetic field communication arrangement 10 ofthe present invention, including a tractor-trailer 12 having a tractorunit 14 and a trailer 16. Arrangement 10 may include an electronicmonitoring system having a sensor data receiver and control module 18 inwireless communication with magnetic communication-based wireless doorcontact sensors 20 and magnetic communication-based wirelessmotion/temperature/noise detectors 22. Module 18, sensors 20 anddetectors 22 may transmit and/or receive long wave (LW) magnetic signalsaccording to the IEEE 1902.1 communication standard, also known asRuBee. In addition, or in the alternative, module 18, sensors 20 anddetectors 22 may transmit and/or receive LW magnetic signals having acarrier signal with a frequency approximately between 100 kHz and 500kHz. In a particular embodiment, the LW magnetic signals have a carrierfrequency of 131 kHz.

Motion/temperature/noise detectors 22 may monitor environmentalparameters within trailer 16, such as movement, temperature, humidity,noise level, etc. while transporting animals, sensitive goods, etc. Aninterior 25 of trailer 16 may be defined by a floor 27, a ceiling 29,and four walls 31, 33, 35, 37 separating interior 25 from the ambientenvironment. One or more doors may be provided in any of floor 27,ceiling 29 and walls 31, 33, 35, 37.

Door contact sensors 20 may detect the presence of an intruder withintrailer 16. More particularly, door contact sensors 20 may detect thestatus of the doors of trailer 16, e.g., whether each of the doors is inan open position or a closed position, and locked or unlocked. It may beimportant for the driver know that the doors of trailer 16 are alwayslocked and/or closed. At any time, if the door of trailer 16 openseither accidentally or intentionally, the opening of the door may bedetected by using wireless door contact sensors 20. The information fromsensors 20 can be immediately transmitted directly to the driver usingwireless magnetic field communication. Each of sensors 20 may transmit asequence of long wave magnetic signals, and each of these signals mayindicate whether a corresponding door in open or closed at the time oftransmission of the signal. Depending upon the door structure, and toincrease fault tolerance of the system, multiple door contact sensors 20can be employed, as shown in FIGS. 1 a-b.

The information from door contact sensors 20 can also be used fordetecting the possible presence of a human intruder. For example, ahuman may open one of the doors in order to gain access to interior 25of trailer 16. At least one of detectors 22 may be in the form of amotion detector that operates in conjunction with one or more doorcontact sensors 20 to thereby provide real time security information tothe driver within tractor unit 14. In one embodiment, a motion detector22 receives the wireless signal from sensor 20 indicating that a doorhas been opened. In response to receiving the signal, motion detector 22may wake up and begin monitoring the space inside trailer 16 for motion.

In another embodiment, motion detector 22 is calibrated to sense themovement and/or shifting of the contents (e.g., animals) of trailer 16during normal operation. However, in response to receiving the wirelesssignal from sensor 20 indicating that a door has been opened motiondetector 22 switches to an alternate state of calibration that may beoptimized to sense the movement of a human within trailer 16. Inaddition to the driver continually being informed and updated withregard to the open/closed position of the trailer door(s) and the stateof motion within trailer 16, the driver may also be informed of whethermotion detector is presently calibrated to sense human or non-humanmovement within trailer 16. Information may be presented to the drivervia an audio speaker 21 and a display monitor 23, each of which may behard-wired to controller 18.

In any of the above-described embodiments, the motion detector(s) maytransmit a sequence of long wave magnetic motion signals. Each of themotion signals may be indicative of whether there is movement within theinterior of the trailer at a respective point in time. Similarly,environmental sensor(s) 22 may transmit a sequence of long wave magneticenvironmental signals. Each of the environmental signals may beindicative of a temperature or a humidity level with the interior of thetrailer at a respective point in time. Control module 18 may receivelong wave magnetic position signals from door contact sensor(s) 20,receive long wave magnetic motion signals from motion detector(s) 22,and receive long wave magnetic environmental signals from environmentalsensors 22. Control module 18 may then control presentation ofinformation on audio speaker 21 and/or video display 23 dependent uponthe received position, motion and environmental signals.

The scope of the invention encompasses types of in-vehicle, magneticfield communication-based sensors and actuators other than those shownin FIGS. 1 a-b. For example, the sensors and actuators contemplated bythe invention may include carbon dioxide (CO2) sensors for airconditioning, contact sensors, daylight sensors, rain sensors, hi-beamsensors, lambda sensors, temperature sensors, air quality sensors, andso on. Possible actuators include, for example, pushbuttons, switches,relays, motors, etc. Several applications such as driver detection andintrusion detection may also fall into this category.

The invention further contemplates the use of magnetic fieldcommunication-based devices in harsh (e.g., heat, in contact with orembedded in metal, disposed within a liquid) environments within avehicle in which it would be difficult and/or hazardous to installand/or operate hard-wired devices. Examples of such harsh environmentsinclude engines, wheels, fuel tanks and fluid reservoirs. Sensors may beembedded within the engine to monitor temperature, fuel quality, etc.The entire node (e.g., including the sensor and the magnetic field-basedcommunication module) may be embedded in, adhered to, disposed within,and/or surrounded by the engine.

Magnetic field sensors may be deployed within the wheel for applicationssuch as tire pressure monitoring. Further, sensors within the wheel mayalso be used to detect wheel alignment, rotational velocity of thewheel, levels of load/balancing, etc.

Magnetic field sensors may also be disposed within fuel tanks and fluidreservoirs, and may perform well therein as magnetic signals are capableof passing through metal/liquid environments. Fuel and other fluids suchas washer fluid, coolant, brake fluid, engine oil, etc. may be idealmonitoring applications for magnetic field sensors, and such sensors mayprovide an efficient way to measure the respective levels and/ortemperatures of these fuels and fluids.

Another application of magnetic field communication-based devicescontemplated by the present invention is in monitoring batteries inelectric and hybrid vehicles. Batteries for electric vehicles are largeand composed of hundreds of cells which may call for constant monitoringof voltage and current. Wired networks are not possible here due toflexibility and future upgradeability requirements. RF based wirelesscommunication on the other hand is hampered by the poor quality of thewireless channel inside the battery pack. Hence, again magneticwave-based communication is an ideal solution for this case.

According to the present invention, magnetic field communication-baseddevices may also be used in applications having precise localizationrequirements. Such applications may include localization of non-variableparts, passive keyless entry (keyfob applications), and intelligenttransport systems. Each of these three applications is described in turnbelow.

The localization of non-variable parts application may address theproblem of localizing/addressing nodes within a wireless network ofnon-variable parts. A magnetic wave based-communication scheme of theinvention may be used to easily localize these non-variable nodes duringthe installation phase. As illustrated in FIGS. 2 a-c, these nodes 24a-c can be placed temporarily at the locations in order to localize thenodes. Node localization may be performed as described in “RobustDistributed Node Localization with Error Management”, Juan Liu, YingZhang and Feng Zhao, MobiHoc '06, May 22-25, 2006; “Vision-Enabled NodeLocalization in Wireless Sensor Networks”, Huang Lee and Hamid Aghajan,In Proc. of Cognitive Systems and Interactive Sensors (COGIS), March2006; “Sextant: A Unified Node and Event Localization Framework UsingNon-Convex Constraints”, Saikat Guha, Rohan Narayan Murty and Emin GunSirer, MobiHoc '05, May 25-27, 2005; “Robust Node Localization forWireless Sensor Networks”, Radu Stoleru, John A. Stankovic and Sang Son,EmNets '07, Jun. 25-26, 2007, and each of these four papers is herebyincorporated by reference herein in its entirety. Examples ofnon-variable nodes to which the localization techniques may be appliedinclude temperature sensors for climate control, park pilot nodes,indicator lights, and so on. Further, these nodes can be placed in theselocations permanently to function as localized group leaders and be partof network hierarchy. The broadcast range or reception range of anRF-based node may be dependent upon the surroundings. In contrast, thebroadcast range or reception range of magnetic signals-based wirelesscommunications may be independent of, and unaffected by, thesurroundings. Hence, magnetic signals-based wireless communications maybe better suited than RF-based wireless communications for localizationsolutions. Potential applications of magnetic signals-based localizationtechniques include: localizing tires, doors, windows, air-conditioningsystem, etc.; unlocking the desired door for keyless entry systems; andmany others.

The passive Keyless Entry (Keyfob) application for magnetic fieldcommunication-based devices may improve upon the poor performance ofknown RF-based key fobs in parking lots or when a large number of othervehicles are nearby. This is poor performance may be primarily due tothe presence of numerous metallic obstructions in such scenarios.Because magnetic wave communication is largely immune to metallicobstructions, the performance of magnetic-based communication devicesmay be better than that of RF devices in the presence of other vehicles.This characteristic leads to another advantage of magnetic field-baseddevices in that the driver detection range within the vicinity of thecar may remain constant regardless of the surroundings, thereby makingmagnetic communication advantageous for implementation in a keylesspassive entry system.

The intelligent transport systems applications for magnetic field-basedcommunication devices may include metered parking, toll collection, lanedetection, automatic traffic light signaling, parking spot validationand car tracking within the parking lot. Magnetic communicationtechnology may be advantageous for use in such applications due to thetechnology's precise localization capability.

Taking the parking lot application as an example, each vehicle mayinclude and carry a low-power magnetic field-based transmitter or “tag”that emits information identifying the vehicle. Electronic readers orreceivers of these identification signals may be provided in the parkinglot for identifying the vehicles within the lot, and in which parkingspace each of the vehicles is disposed. The readers may be employed forevery single/pair/quad parking spots, as shown in FIGS. 3 a-d. Asschematically indicated in FIG. 3 a, a respective one of readers 26 ₁through 26 ₈ may be associated with each of parking spaces 28 a-h. Inanother embodiment depicted in FIG. 3 b, a respective one of readers 126₁ through 126 ₄ may be associated with each of four pairs 28 a/b, 28c/d, 28 e/f, 28 g/h of parking spaces. In yet another embodimentdepicted in FIG. 3 c, a respective one of readers 226 ₁ through 226 ₄may be associated with each of four pairs 28 a/e, 28 b/f, 28 c/g, 28 d/hof parking spaces. In still another embodiment depicted in FIG. 3 d, arespective one of readers 326 ₁ through 326 ₂ may be associated witheach of two quadruplets 28 a/b/e/f, 28 c/d/g/h of parking spaces. Ascompared to RF technology, the magnetic wave communication may result ina reduced number of false alarms for the aforementioned applications.

Illustrated in FIG. 4 a is one embodiment of an engine having fourmagnetic field-based sensors 30 a-d, which may be temperature sensors,for example. Sensor 30 a is adhered to, welded to, or otherwise attachedto an inner wall of an air inlet 32. Sensor 30 b is embedded in an innerwall of a fuel inlet 34. That is, the inner wall of inlet 34 may have arecess 36 for receiving sensor 30 b therein such that an exposed surface38 of sensor 30 b is flush with the inner wall and a smooth, continuoussurface is thereby provided. Thus, sensor 30 b does not impede the flowof fuel into the engine. Sensor 30 c is similarly embedded in a topsurface of a piston 40. Sensor 30 d is attached to a bottom surface ofpiston 40. Alternatively, sensor 30 d could be embedded into a cylinderwall, as indicated with dashed lines at 42. All of the walls andstructure of the engine may be formed of metal, such as steel, exceptpossibly for sensors 30 a-d.

Illustrated in FIG. 4 b is one embodiment of an automotive radiator 44having a magnetic field-based sensor 46, which may be a temperaturesensor, for example. Sensor 46 is adhered to, welded to, or otherwiseattached to a wall 48 of radiator 44. However, in another embodiment,sensor 46 is embedded in an inner surface 50 of wall 48. As shown inFIG. 4 b, sensor 46 may be installed at a vertical level such thatsensor 46 is submerged in liquid coolant 52 during normal operation.Radiator 44 may be formed of metal such that sensor 46 is surrounded bythe metallic structure of radiator 44.

Illustrated in FIG. 4 c is one embodiment of an automotive windshieldwasher reservoir 58 having a magnetic field-based sensor 60, which maybe a temperature sensor, for example. Sensor 60 is adhered to, weldedto, or otherwise attached to a wall 62 of reservoir 58. However, inanother embodiment, sensor 60 is embedded in an inner surface of wall62. As shown in FIG. 4 c, sensor 60 may be installed at a vertical levelsuch that sensor 60 is submerged in liquid washer fluid 64 during normaloperation. Reservoir 58 may be formed of metal, or may be formed ofplastic and may be surrounded by metal, such that sensor 60 issurrounded by a metal structure. Also submerged in fluid 64 may be amotor assembly including a motor 66 and a control module 68. Motor 66may pump fluid 64 onto the windshield in response to the driveractuating a control button, for example. Control module 68 may have amagnetic field-based receiver for receiving long wave magnetic signalsfrom sensor 60 or from a central controller (not shown). In one exampleembodiment, sensor 60 detects whether fluid 64 is in a liquid state or afrozen solid state. If long wave (LW) magnetic signals from sensor 60indicate that fluid 64 is frozen, then long wave (LW) magnetic signalsmay be transmitted to module 68, either directly from sensor 60 or fromthe central controller, instructing module 68 to inhibit operation ofmotor 66 in response to the driver actuating the control button. Thus,damage to motor 66 from attempting to operate in a frozen environmentmay be avoided. Further, the central controller may send a signal to adisplay or audio speaker in the passenger compartment to inform thedriver that the washer fluid is frozen. When sensor 60 senses that fluid64 as liquefied, then sensor 60 may transmit another signal soindicating to the central controller, and the driver may be notifiedthat the windshield washer pump is now operable.

One embodiment of an automotive communication method 500 of the presentinvention is illustrated in FIG. 5. In a first step 502, a sensor isinstalled within a vehicle such that the sensor is submerged in a liquidduring operation of the vehicle and/or substantially surrounded by ametallic structure during operation of the vehicle. For example, asensor 46 (FIG. 4 b) may be installed in a vehicle such that sensor 46is attached to a wall 48 of radiator 44. When radiator 44 is filled withliquid coolant during operation, sensor 46 may be submerged in thecoolant. Further, sensor 46 may be surrounded by the metallic structureof radiator 44. As another example, each of sensors 30 a-d (FIG. 4 a)may be installed in a vehicle such that each of sensors 30 a-d issurrounded by the metallic structure of the vehicle's engine. Suchinstallation positions may result in poor performance if any of thesesensors relied on RF communication.

In a second step 504, a long wave magnetic sensor signal is transmittedfrom the sensor. The sensor signal is indicative of a condition sensedby the sensor. That is, any of sensors 30 a-d, 46 may transmit a signalconforming to the IEEE 1902.1 standard and/or having a carrier frequencyof approximately between 100 kHz and 500 kHz. The signal may containinformation pertaining to a condition sensed by the sensor, such astemperature, humidity, voltage, force, pressure, etc.

Next, in step 506, the signal is wirelessly received at a controllerdisposed within the vehicle. More particularly, a central controller(e.g., an engine control module) may include a receiver configured toreceive long wave magnetic signals.

In a final step 508, receipt of the signal at the controller isresponded to by adjusting a display and/or a setting within the vehicle.For example, a temperature gauge or a temperature warning light on adashboard of the vehicle may be adjusted to reflect the temperaturesensed by the sensor. As another example, an engine control module maychange the fuel-to-air mixture in the engine to optimize fuel efficiencyat the current temperatures at various locations within the engine assensed by sensors 30 a-d.

One embodiment of a method 600 of the invention for monitoring thepresence of vehicles within a predetermined space is illustrated in FIG.6. In a first step 602, a respective long wave magnetic identificationsignal is broadcast from each of a plurality of vehicles. Each of theidentification signals uniquely identifies the vehicle from which thesignal is broadcasted. For example, in the embodiments illustrated inFIGS. 3 a-d, each vehicle disposed in any of parking spaces 28 a-h maycontinuously or periodically transmit long wave magnetic identificationsignals specifying that particular vehicle's vehicle identificationnumber (VIN). These signals may be broadcasted by the vehicle at alltimes, even when the vehicle's engine and ignition are turned off.

In a next step 604, a plurality of long wave magnetic signal readers areused to receive the identification signals from the vehicles. Each ofthe readers receives the identification signals from vehicles disposedwithin a respective portion of the predetermined space. In theembodiment of FIG. 3 a, long wave magnetic signal readers 26 ₁₋₈ mayreceive identification signals transmitted by any vehicles in parkingspaces 28 a-h, respectively. For example, each of readers 26 ₁₋₈ may becentrally located above or below its respective one of parking spaces 28a-h. Because of the short broadcast range or reception range of longwave magnetic signals, each of readers 26 ₁₋₈ so positioned may becapable of receiving the identification signal of only a vehicle parkedwithin two to three feet of the reader in the reader's correspondingparking space. Taking as another example the embodiment of FIG. 3 b,each of readers 126 ₁₋₄ may be centrally located above or below theborder between an adjacent pair of the eight parking spaces 28 a-h.Because of the short broadcast range or reception range of long wavemagnetic signals, each of readers 26 ₁₋₄ so positioned may be capable ofreceiving the identification signal of only vehicles parked within twoto three feet to either side of the reader in the reader's pair ofcorresponding parking spaces.

In a final step 606, the received identification signals areautomatically responded to by recording the identifications of thevehicles in association with each of the portions of the predeterminedspace and/or transmitting a response signal. That is, readers 26 ₁₋₈ maybe each connected to a central controller and memory device such thatthe identification of which vehicle is parked in which parking spot maybe recorded. In addition, or in the alternative, a response signal maybe transmitted in the form of a signal to an accounting serverinstructing that the identified vehicles' accounts be charged with themonetary fee for parking for a particular time period. Another exampleof a response signal may be a signal to an electronic display sign alongthe border of the parking lot indicating that the parking lot is full(e.g., each parking space is occupied), or that a particular row ofparking spaces are full, or indicating the locations of parking spacesthat are unoccupied. The display sign may then produce a graphic and/ortextual display conveying to human viewers the information indicated inthe signal. Thus, a response signal, among other possibilities, mayindicate a respective monetary fee to be charged to each of the vehicleswhose identification signals are received, may indicate whether avehicle whose identification signal is received is authorized to park inthe portion of the predetermined space, or may control a traffic light,such as at an intersection of two streets. More particularly, in thetraffic control scenario, readers could detect whether vehicles arestopped at the intersection waiting for the light to change. If so, thenthe lights may be changed immediately such that the oncoming crosstraffic is given a yellow light and then a red light, and the stoppedvehicle is given a green light, for example.

A specific example of a parking garage arrangement 700 which may employmethod 600 is illustrated in FIG. 7. Each of a plurality of readers 26monitors a pair of adjacent parking spaces 28, and each reader 26 may beable to discern whether both, one, or neither of its corresponding pairof parking spaces is occupied. Readers 26 may report the occupancystates of parking spaces 28 to a controller 54 which controls anelectronic display sign 56 accordingly. Sign 56 may inform a viewer ofwhere unoccupied parking spaces can be found in the garage. Each of themultiple parking spaces monitoring by a single reader may be labeled andreferred to with a common numerical identifier (e.g., “spaces 24” or“37” as in FIG. 7), which provides enough specificity for theviewer/driver to find the group of parking spaces and visually find anempty one among the group of parking spaces.

While this invention has been described as having an exemplary design,the present invention may be further modified within the spirit andscope of this disclosure. This application is therefore intended tocover any variations, uses, or adaptations of the invention using itsgeneral principles. Further, this application is intended to cover suchdepartures from the present disclosure as come within known or customarypractice in the art to which this invention pertains.

What is claimed is:
 1. An automotive communication method, said methodcomprising the steps of: installing a first sensor at a first locationwithin a vehicle and installing a second sensor at a second locationwithin the vehicle, at least one of the first and the second sensorbeing substantially enclosed within a metallic structure duringoperation of the vehicle; transmitting a first long wave magnetic sensorsignal wirelessly from the first sensor and a second long wave magneticsignal from the second sensor, at least one of the first and the secondlong wave magnetic signals being transmitted through the metallicstructure, the first and the second long wave magnetic sensor signalsbeing indicative of a sensed condition; wirelessly receiving the firstand the second long wave magnetic sensor signals at a controllerdisposed within the vehicle; localizing the first and the second sensorswith respect to each other and with respect to the vehicle at thecontroller using the first and the second long wave magnetic sensorsignals; and responding to the receipt of the first and the second longwave magnetic signals signal at the controller by adjusting a displayand/or a setting within the vehicle.
 2. The method of claim 1 whereinthe first and the second long wave magnetic signals are modulated with acarrier frequency of approximately between 100 kHz and 500 kHz.
 3. Themethod of claim 1 wherein the controller is disposed in the vehicle suchthat the controller is substantially enclosed within a second metallicstructure during operation of the vehicle, the first sensor and thesecond sensor being disposed outside of the second metallic structure.4. The method of claim 1 wherein at least one of the first and thesecond sensors is associated with a motor of the vehicle and thecondition sensed by the at least one of the first and the second sensorscomprises a condition associated with the motor.
 5. The method of claim4 further comprising directing operation of the motor based on thecondition associated with the motor sensed by the at least one of thefirst and the second sensors.
 6. The method of claim 1 wherein the firstsensor is submerged in liquid washer fluid within a windshield washerreservoir.
 7. The method of claim 1, wherein the localization includescomputing a two-dimensional and/or a three-dimensional position of thefirst sensor and the second sensor with respect to each other.